The problem is that it is a channeling skill, meaning the player is STUNNED for the duration of the skill while the enemies captured are disabled to move BUT can still attack.
The skill also ends when your main target dies cancelling the arrest skill to other enemies captured.
Its targeting area is a slim cone shape, which also a factor of arresting fewer enemies.
My suggestions for improving the skill is to:
Remove the channeling mechanic and change it into something similar like Linker’s electric shock where the enemies are tethered to the player while the player can still move around and do other skills.
The skill effect shouldnt be reliant of the main target’s hp. If your main target dies, it should not cancel the arrest skill for the other captured enemies.
change the targeting area into a semi circle. With this we can fully utilized the number of enemies we can capture.
Arrest is currently underwhelming atm. But I see the skill as the squire’s version of Lethargy plus having the opponents immobile.